WASHINGTON — U.S. aircraft are continuing their assault on Islamic State militants in Iraq, conducting six airstrikes overnight to help solidify Iraqi and Kurdish forces' efforts to retake and maintain control of the Mosul Dam.

The Islamic State group had gained control of large swaths of western and northern Iraq and had taken the dam, but Iraqi and Kurdish forces, backed by a barrage of U.S. airstrikes were able to push the militants back and regain control of the dam. U.S. officials had worried that militants would breach the dam and flood parts of Baghdad.

U.S. officials say the strikes are part of an effort to create a safe perimeter around the dam. The military said the latest strikes destroyed or damaged three Humvees, multiple roadside bombs and another insurgent vehicle.